1. Field of the Invention
Embodiments of the present invention disclose devices and methods for treating the collapse of structures within the nose that form the passageways for airflow during inhalation.
2. Description of the Related Art
The airflow resistance provided by the airways during breathing is essential for good pulmonary function. The nose is responsible for almost two thirds of this resistance. Most of this resistance occurs in the anterior part of the nose. This region is called the nasal valve, and it acts as a flow-limiter.
The nasal valve was originally described by Mink in 1903. It is divided into external and internal portions. The external nasal valve is formed by the columella, the nasal floor, and the nasal rim (or caudal border of the lower lateral cartilage). The nasalis muscle dilates this portion during inspiration. The internal nasal valve accounts for the larger part of the nasal resistance. It is located in the area of transition between the skin and respiratory epithelium, and it is usually the narrowest part of the nose. The internal nasal valve is the better-known valve and is often referred to as the nasal valve.
The two terms should be differentiated because the internal nasal valve or “nasal valve” accounts only for the aperture between the nasal septum and the caudal border of the upper lateral cartilage (ULC). The angle formed between them is normally between about 10°-15°.
The nasal valve area is formed by the nasal septum, the caudal border of the ULC, the head of the inferior turbinate, and the pyriform aperture and the tissues that surround it. This area is responsible for more than two thirds of the resistance produced by the nose.
In 1894, Franke performed nasal-flow experiments in models and cadavers and found that whirl formation occurred near the head of the turbinate during calm breathing. The term nasal valve was first coined by Mink in 1903. He developed this concept further in 1920, suggesting that the greatest area of resistance was in the limen nasi or the union of the lobular cartilage and ULCs.
In 1940, Uddstromer found that 70% of the resistance of the nose was produced in the nasal valve area and the remaining 30% was due to the nasal fossa. Van Dishoeck further investigated the mechanisms of the nasal valve in 1942, and in 1970, Bridger and Proctor wrote about a “flow-limiting segment” that included the limen nasi and the pyriform aperture. In 1972, Bachman and Legler found the pyriform aperture to have the smallest cross-sectional area of the nasal airway.
In 1983, Haight and Cole continued the study of Bridger and Proctor and demonstrated that the maximal nasal resistance was localized near the pyriform aperture and depended on engorgement of the head of the inferior turbinate.
As many as 13% of the patients with chronic nasal obstruction have nasal valve collapse. Of these patients, 88% have unilateral collapse.
External nasal valve collapse is often found in patients who do not have a history of trauma or surgery. These patients commonly have an overprojecting nose with extremely narrow nostrils. Another cause can be an extremely wide columella.
Types of internal nasal valve collapse can be differentiated depending on the structure that caused the collapse. In many cases, more than one structure is affected. The most common cause is probably septal deviation. The second cause is collapse secondary to rhinologic surgery, especially after removal of the nasal roof.
In 1987, Kasperbauer and Kern developed a comprehensive classification; however, the classification below depends on the anatomical area.
Deviations of the caudal septum are the most common cause of valvular collapse. They are usually secondary to trauma. The septum can be overly thick in the valvular area, decreasing the space in it. Also, an absence of cartilage in this area leaves a flaccid septum that moves during inspiration.
Thickened cartilage can compromise an adequate aperture. The cartilage can also be twisted, deflected, or associated with excessive return of the caudal border. An absence of cartilage, either congenital or iatrogenic, can produce a flaccid valve that collapses during inspiration.
Overresection during rhinoplasty can weaken the cartilage and cause inspiratory collapse. Deformation of the cartilage can be a result of trauma or congenital malformations of the cartilage.
Trauma or previous surgery can create webs or stenosis in the valvular area. The tissue can also be too thick, reducing the lumen of the valve. This can be a result of inflammation or hypertrophy.
Hypertrophy of the inferior turbinate can significantly increase nasal resistance. Several studies have demonstrated that the head of the turbinate is responsible for most of this increase. In comparison, the body and tail of the turbinate play minor roles in nasal resistance. The increase in size can be secondary only to mucosa or bone hypertrophy.
Although uncommon, some patients may have deformities of the pyriform aperture that reduce the space of the nasal valve. The first description the authors found of a congenital stenosis of the pyriform aperture was made by Brown et al in 1988; other reports have followed, such as Ramadan, 1995; Fornelli, 2000; and Lee, 2002. A more common cause of obstruction is the osteotomy made during a rhinoplasty. In particular, the type known as low-to-low is blamed for excessive narrowing of the pyriform aperture. Some modifications to this procedure allow an osteotomy to be performed without compromising the space in the valve.
Rhinoplastic procedures are particularly prone to disturbing the nasal valve area. Hump removal affects the nasal valve in several ways. If the hump is particularly large, separation of the ULC can be necessary. Resection of the T-shaped area of the dorsal border of the septum produces a narrower area in the roof. If the mucosa in the valve is not protected during the surgery, which occurred with the use of many older techniques, scarring of the valve can lead to structure formation or stenosis of the valve. In reduction rhinoplasties, the cross-sectional area of the overall nose is reduced. This increases the resistance to airflow. If the nasal valve is not properly repaired during the surgery, patients may report nasal obstruction after the surgery, even if this was not reported preoperatively. Overresection of the lower lateral cartilage can lead to pinching and inspiratory collapse.
Age is another factor to consider. The relaxation of tissues may eventually produce a flaccid valve. In these cases, surgery of the valve can correct the loss of patency.
The internal nasal valve works as a flow-limiting area. The fixed part of the valve is composed of the septum and the pyriform aperture. The ULC and the mucosa of the turbinate act as the mobile part. When air is inspired, it is forced through this narrow area, increasing its speed and pressure. Just after passing the valve, the air expands in the bony cavum, creating turbulence that promotes contact between the air and the mucosa. In this way, the inspired air is cleansed of particles, humidified, and heated or cooled (depending on its temperature).
Because it is the narrowest part of the nose, the nasal valve can be affected by minute alterations of the nasal anatomy that would not be important in other areas. The angle between the ULC and the nasal septum is typically between about 10°-15°. Internal nasal valve collapse occurs when, for some reason, this angle is diminished. The result is an increase in nasal resistance to airflow; consequently, the patient reports nasal obstruction. The opposite is known as ballooning. In this case, the nasal valve is excessively open.
The increase in nasal resistance is also related to abnormalities of pulmonary function. These changes in pulmonary function return to normal after septal surgery is performed and nasal resistance is decreased.
Patients primarily report nasal obstruction. Other symptoms are crusting and bleeding, but these are more often associated with septal deviation.
Diagnosis can be difficult if the physician does not visualize the valvular area. Examining the valve without disturbing it with a nasal speculum is important because the speculum usually opens the valve. Sometimes, trimming the vibrissae is necessary to obtain a clearer view of the valve. Another method is to use a 0° endoscope.
The Cottle test is useful to evaluate nasal valve stenosis. The cheek of the evaluated side is gently pulled laterally with 1-2 fingers, which opens the valve. The examiner then asks the patient to breathe and evaluates if breathing is better before or after pulling the cheek. A positive test result is when the patient feels less resistance with the valve opened. This test is easy and quick to perform.
The internal nasal valve is limited medially by the nasal septum. Laterally, in its superior part, it is limited by the caudal border of the ULC, where it forms the limen nasi with the cephalic border of the lobular cartilage. The angle between the septum and the ULC is generally between about 10°-15° in patients of Caucasian descent. Patients of other ethnic backgrounds can demonstrate great variability in this septum-ULC angle measurement. In this area, epithelium shifts from the skin of the vestibule to the respiratory mucosa of the bony cavum.
The pyriform aperture continues the limit of the valve from the ULC to the floor. The head of the inferior turbinate is immediately posterior to the pyriform aperture and plays an important role in the function of the valve, which is the reason it is also considered part of the internal nasal valve. In some patients, particularly white persons, the caudal border of the ULC scrolls externally in what is called the returning of the ULC. When this returning is excessive, it can produce valve collapse.
In addition to the typical reasons to avoid surgery (e.g., bleeding disorders), other contraindications include excessive scarring due to multiple previous surgeries, which may compromise the outcome of the procedure, the presence of cheloid scarring, and unrealistic patient expectations.
Imaging studies such as CT scanning of paranasal sinuses can be performed to, for example, obtain coronal views which can provide good information on the patency of the nasal valve, especially the area under the nasal dorsum (nasal valve area), which is sometimes difficult to visualize. However, these studies are expensive and should not be considered a substitute for comprehensive physical examinations.
Other diagnostic tests that can performed include rhinomanometry and acoustic rhinometry. Rhinomanometry aids in evaluating the airflow resistance offered by each cavity but does not provide information about the location of the obstruction. Acoustic rhinometry is relatively new, as it was introduced in the late 1980s, and it can provide information about the cross-sectional area of the nose and about the position of obstructions. Results from the anterior portion of the nose tend to be more accurate than results from the posterior portion, making this test particularly suitable for evaluating the valve. Acoustic rhinometry can be used to evaluate the symmetry of nasal areas.
The nasal valve is better explored without instruments because tools can open the valve and produce the false impression that the area is normal. A headlight and an endoscope are the only necessary instruments to examine the nasal valve. In many male patients (and some females), the vibrissae are thick, making direct visualization of the area difficult. If this occurs, one option is to trim them until the valve can be visualized.
The Cottle test is a good method to examine the vestibular portion of the nasal valve. It consists of pulling the nasolabial fold upward and laterally and asking the patient if breathing is better. An affirmative answer implies that a collapse of the valve is present on that side. A negative answer means the cause of the obstruction is elsewhere in the nose. A false-positive result can occur in patients with collapse of the nasal ala. False-negative results are observed in patients with scars or webs in the valve that prevent it from opening. False-negative results also occur in those with narrowing of the pyriform aperture secondary to congenital malformation or after an excessive narrowing of the nasal base with an osteotomy.
When the valvular collapse is secondary to inflammation of the mucosa covering the valve (e.g., secondary to allergic rhinitis or infection), proper treatment, such as anti-inflammatory agents or antibiotics, can help remedy the problem.
Collapse secondary to mechanical obstruction is more common. In this case, surgery is the only solution. Some patients use a self-adhesive stent that opens the nasal valve; however, this is only a temporary solution.
Several surgical techniques are used to correct a stenotic or collapsed nasal valve. Depending on the type of pathology, the surgeon can choose to use one or several methods. The scope of techniques varies from sutures to the application of grafts. The common goal is to open the valve, restoring the appropriate anatomy. Explaining each technique is beyond the scope of this article; however the following is a summary of these techniques depending on the structure modified.
A valvuloplasty is the surgery historically used to reconstruct the nasal valve. The goal of this surgery is to open the valve by removing the returning ULC and trimming the caudal border of the cartilage. It is not the only technique used to correct valvular alterations, but it provides an excellent view of the caudal border of the ULC and can be used in conjunction with other techniques. Because the valve is formed by several different structures, other techniques may be necessary, depending on the type of deformity that produced the stenosis.
The goal of this procedure is to expose the caudal border of the ULC to correct any deformity (e.g., resection of the caudal border of the ULC, excessive returning of the ULC). The following preliminary steps can be taken when performing this procedure: expose the caudal border of the ULC through an intercartilaginous incision, avoid damaging the valvular mucosa in order to decrease the risk of a synechia, and place intercartilaginous incisions 1-2 mm caudal to the border of the ULC. The area of transition from skin to respiratory epithelium is prone to developing unwanted scarring or synechiae. Then the following steps can be taken:
Undermine the skin over the dorsum.
To obtain better exposure, gently retract the alar margin of the nostril with a 10- or 12-mm double hook.
Grasp the caudal border of the ULC with an Adson-Brown or similar forceps.
Dissect the mucosa in the underside of the ULC with the tip of a Walter or curved Iris scissors.
Similarly separate the upper side of the ULC from the subcutaneous tissue until the caudal border is completely visible.
Repeat the same procedure if the dorsum is visible from both sides.
Almost any deformity of the ULC can be identified this way.
If a septoplasty or rhinoseptoplasty was performed and the caudal border of the septum was resected, resect a similar amount of the caudal border of the ULC. This maintains the proportions between the septum and the ULC.
Resection of the caudal border of the ULC reduces its flexibility. To maintain it, removing a small triangle near the septum may be necessary.
If another deformity is present, direct surgery to correct it. For example, if the ULC is twisted, a batten may be necessary to straighten it.
Spreader grafts can be inserted and fixed through this incision to increase the cross-sectional area of the nose.
When intercartilaginous incisions do not allow enough space to see and work because of the complexity of the stenosis, an open approach provides excellent exposure (i.e., when spreader grafts and flaring sutures are applied in the same procedure).
A dry field is important in this surgery because the space is limited and bleeding can obstruct the visual field and make the procedure time consuming. To avoid this, the cul-de-sac can be infiltrated 5-10 minutes prior to the incision. Apply only a small amount of lidocaine and epinephrine (Octocaine with epinephrine [2%], Xylocaine with epinephrine [2%]). Approximately 0.5 mL is needed in each valve to avoid distortion of the structures. Help from an assistant is invaluable.
Suturing of the intercartilaginous incision is performed at the end of the surgery, when all other maneuvers have been completed. Some prefer to use catgut or 4-0 Vicryl with ophthalmic needles. These small curved needles are easy to handle in the confined space of the vestibule.
Normal preoperative examinations can be performed, and no special care is required. The surgery is often performed in combination with septoplasty or rhinoseptoplasty. Local or general anesthesia can be used.
Because the valve is formed by several structures, the surgery is directed toward realigning the obstructing parts.
If a caudal deviation is causing the obstruction, a septoplasty can correct the problem. Septoplasty is a difficult surgery because caudal deviations are commonly complex deformities of the septal framework and obtaining a completely straight septum proves to be a frustrating task. In some cases, obtaining straight cartilage from the posterior septum and transplanting it is preferable. This is particularly true in those patients with horizontal fractures of the caudal septum (e.g., Chevallet fractures). The use of battens is sometimes necessary to keep the repaired septum straight.
The nasal roof can be excessively narrowed after rhinoplasty or with congenital or traumatic deformities. In these cases, the use of spreader grafts, as described by Sheen in 1984, is particularly useful. They keep the nasal profile straight, and they also increase the cross-sectional area of the entire nasal valve.
If the cartilage is thick or if excessive returning of the caudal border of the cartilage occurs, modification is possible by resecting the caudal border and reshaping the valve. This is commonly a surgery performed concomitantly with septoplasty. Also, the previously mentioned spreader grafts can modify the position of the cartilage, allowing the valve to open. In case the cartilage is absent, a graft can be fashioned from septal or auricular cartilage. Another method described to open the nasal valve is to apply a flaring suture that lifts the ULCs. A combination of both techniques has recently been reported to have the best results. The ULC can be sutured using several different techniques, including suspension sutures (Lee, 2001) and mattress sutures (Ozturan, 2002).
When the alar cartilage is weakened after surgical overresection or trauma, its rigidity must be restored. The basic method consists of applying a batten of cartilage to keep the lobule rigid during inspiration. A method described by O'Halloran in 2003 consists of the removal of excessive skin in the valvular area through an incision anterior to the LLC.
Although complete resection of the turbinate is best avoided, conservative resection (or manicuring) of the head of the turbinate significantly decreases the total resistance offered by the internal valve. This procedure, when performed properly, is a useful tool when the other areas are difficult to correct. Unless hypertrophy is extremely large, resecting more than 2 cm from the head typically is not necessary because the airflow follows a superior direction afterwards.
Narrow pyriform apertures should be handled depending on the origin of the constriction. Congenital pyriform stenosis can be produced from an excess of bone. This bone can be drilled away through a sublabial approach. If the stenosis was produced by an excessive narrowing of the nasal bones in a previous surgery, it can be handled with resection of a small wedge of bone in the narrowest area. Another approach is to displace the bones laterally (outfracture) after performing new osteotomies. In this case, performing medial and lateral osteotomies is recommended. If neither procedure is successful, conservative resection of the head of the inferior turbinate is an alternative plan. In many patients, more than one procedure is necessary to open the valve.
This situation is difficult to handle. Obstructive scarring is common after surgery. Resection of the synechia or scarring is performed with scissors. Because some synechia and scars are quite thick, a good method is to clamp the valve with a forceps for 5 minutes before the procedure in order to obtain better hemostasis. Good results have been obtained by separating both sides of the valve with a silicone sheet (Silastic). Because the author routinely uses silicone (Silastic) splints for septal surgery, the splint must simply be cut into a proper shape and size and then sutured to the septum with nylon 3-0 or 4-0 suture. A contralateral splint is recommended to avoid unnecessary damage to the mucosa.
Incisions can be closed with 4-0 catgut or Vicryl, preferably with ophthalmic needles to facilitate the closure. A typical dressing can be applied to the rest of the nose, depending on the surgery performed (e.g., dressing and cast for rhinoplasty).
The need for hospitalization following these types of procedures depends on the type of anesthesia used, the recovery of the patient, and the evaluation of the physician. Because the procedures are primarily performed in combination with septoplasty, the same care used following septoplasty is applicable for these procedures.
Thus, there remains an unmet need in the art for non-traumatic, non-surgical treatments for the collapse of structures within the nose that form the passageways for airflow.